Thermal-diffusion synthesis of thick molybdenum disulphide coatings on steel substrates

For the last decades special attention has been paid to technologies of deposition of molybdenum disulphide (MoS2) coatings and films because of their outstanding tribological properties. Nowadays, PVD methods are successfully used in production of high-performance MoS2 coatings. However, high production cost of the methods is the strong factor limiting their wide industrial application. In this paper, an alternative method of deposition of MoS2 coatings (thermal-diffusion synthesis) is presented. This method of synthesis of MoS2 coatings comprises two stages: (a) formation of the molybdate and molybdenum oxide layer on the surface of the steel substrate; (b) treatment of the substrate in the vaporous sulfur environment to form MoS2. Thickness of the MoS2 coatings varied within 5–60 microns, formation of transition zone on the coating/substrate boundary was observed. Friction tests carried out under ambient conditions at 625–1250 MPa contact pressure showed values of the friction coefficient 0.17–0.07, respectively.